OFFSET
7,2
EXAMPLE
a(7) = 1: {1,2,3,4,5,6,7}-> 16/25/34/7.
a(8) = 2: {1,2,3,5,6,7,8}-> 17/26/35/8, {1,2,3,4,5,6,7,8}-> 18/27/36/45.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Alois P. Heinz, Oct 01 2014
STATUS
approved